Gas-phase thermochemistry of the early cationic transition-metal sulfides of the second row: YS+, ZrS+, and NbS+

The gas-phase reactivity of YS+, ZrS+, and NbS+ towards oxygen-transferring reagents such as H2O, CO, CO2, and COS is investigated using guided-ion beam (GIB) and Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry. A lower limit of D0(M+–S) > 4.50 ± 0.04 eV for the sulfur binding energy is derived from the exothermic formation of MS+ in the reaction of all three atomic metal ions, M+, with CS2. Upper limits for D0(M+–S) are determined by collision-induced dissociation of MS+ with Xe. The O-transfer experiments carried out in the GIB instrument lead to several estimates for D0(M+–S), which are further refined by equilibrium constants Keq derived from the reaction MS+ + H2O → MO+ + H2S and its reverse. Overall assessment of the results from ion–molecule reactions, collision-induced dissociation, and equilibrium measurements yields the 0 K bond energies of D0(Y+–S) = 5.49 ± 0.18 eV, D0(Zr+–S) = 5.69 ± 0.10 eV, D0(Nb+–S) = 5.20 ± 0.21 eV, D0(Y+–CS) = 1.42 ± 0.08 eV, D0(Zr+–CS) = 2.67 ± 0.11 eV, and D0(Nb+–CS) = 2.51 ± 0.11 eV, and heats of formation for ΔfH0(YOS+) = 6.59 ± 0.37 eV, ΔfH0(ZrOS+) = 8.45 ± 0.33 eV, ΔfH0(NbOS+) = 9.05 ± 0.27 eV, ΔfH0(YS2+) = 6.96 ± 0.70 eV, and ΔfH0(ZrS2+) = 9.34 ± 0.73 eV.